In a typical cellular telephone system, mobile stations (for example, cellular telephones) communicate with base stations using wireless communication links. The base stations are coupled to a base station controller, which is coupled to a mobile switching center. Communications from the mobile station are sent to the base station controller. The base station controller may forward the communications to another mobile station using the same or another base station in the cellular network. Alternatively, the base station controller may forward the communications to the mobile switching center for communication to another network, such as another cellular network, the public switched telephone network, the Internet, or any other appropriate networks.
As a mobile station moves away from a base station, the ability of the mobile station to communication with the base station may be impaired. However, as this impairment of communications occurs, other base stations in the same cellular network may come within range of the mobile station. Therefore, the responsibility for supporting communications with the mobile station may be transferred from one base station to another. This transfer of responsibility (or “handoff”) is typically controlled by the mobile switching center and/or the base station controller, not by the mobile station. Handoffs within a single cellular network are typical and may often be performed with minimal effect on communications with the mobile station. However, a handoff between base stations in different cellular networks, when available, is more complicated and often has a detrimental effect on communications with the mobile station.
Furthermore, mobile stations are increasingly being outfitted with additional communication interfaces to allow the mobile station to communicate with other types of networks and stand-alone devices. As with handoffs between different types of cellular networks, handoffs of communications between these different technologies is also difficult or unavailable.